Method for supporting flexible resource allocation in wireless communication system, and device therefor

ABSTRACT

Disclosed is a method by which an operating station (STA) transmits a signal in a multiple user (MU) scheme in a wireless LAN (WLAN) system. In the present method, the STA configures a wireless frame, which includes a data field for data transmission and a signaling (SIG) field including control information, wherein the SIG field includes a SIG A field, which includes bandwidth information indicating the whole bandwidth having a bandwidth of 2n times that of 20 MHz, and a SIG B field, which includes user specific information. Here, the bandwidth information of the SIG A field additionally indicates whether the whole bandwidth includes one or more 20 MHz bands (null channel), which are not used in the data transmission.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, andmore particularly, to a method and apparatus for enabling efficient datatransmission on a non-contiguous channel or a channel having a bandwidththat is not supported by a legacy system in a wireless local areanetwork (WLAN) system.

BACKGROUND ART

While the proposed method is applicable to various types of wirelesscommunication, a WLAN system will be described as an exemplary system towhich the present disclosure is applicable.

WLAN Standards have been developed as institute of electrical andelectronics engineers (IEEE) 802.11. IEEE 802.11a and b use anunlicensed band at 2.4 GHz or 5 GHz. IEEE 802.11b provides atransmission rate of 11 Mbps and IEEE 802.11a provides a transmissionrate of 54 Mbps. IEEE 802.11g provides a transmission rate of 54 Mbps byapplying orthogonal frequency division multiplexing (01-DM) at 2.4 GHz.IEEE 802.11n provides a transmission rate of 300 Mbps for four spatialstreams by applying Multiple Input Multiple Output (MIMO)-OFDM. IEEE802.11n supports a channel bandwidth of up to 40 MHz and, in this case,provides a transmission rate of 600 Mbps.

The above-described WLAN standards have evolved into IEEE 802.11ac thatuses a bandwidth of up to 160 MHz and supports a transmission rate of upto 1 Gbits/s for 8 spatial streams and IEEE 802.11ax standards are underdiscussion.

DISCLOSURE OF THE INVENTION Technical Task

An object of the present disclosure is to provide a method and apparatusfor efficiently transmitting a signal by a station (STA) in a wirelesscommunication system.

Specifically, the present disclosure is intended to efficiently define aresource allocation scheme for orthogonal frequency division multipleaccess (OFDMA) or multi-user multiple input multiple output (MU-MIMO) ina future-generation WLAN system conforming to institute of electricaland electronics engineers (IEEE) 802.11ax among wireless communicationsystems.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present disclosure are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present disclosure could achieve will be more clearlyunderstood from the following detailed description.

Technical Solution

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, accordingto one embodiment, a method of transmitting a signal, which istransmitted by an STA (station) operating in a wireless LAN (WLAN)system using a multi user (MU) scheme, includes the steps of configuringa radio frame in which a signaling (SIG) field including controlinformation and a data field for transmitting data are included, whereinthe signaling field is configured to include an SIG A field includingbandwidth information indicating the whole bandwidth having a bandwidthwider than 20 MHz as much as 2^(n) times and an SIG B field includinguser specific information, and transmitting the radio frame to one ormore other STAs. In this case, the bandwidth information of the SIG Afield additionally indicates whether or not the whole bandwidth containsone or more 20 MHz bands (null channel) not used for transmitting data.

The SIG B field can additionally include information indicating alocation of the null channel.

Preferably, the SIG B field can include a common part including commoncontrol information and a user specific part including the user specificinformation and the information indicating the location of the nullchannel can be included in the common part.

The bandwidth information of the SIG A field may have a form of a bitsequence of a prescribed length, first region values of the bit sequenceindicate that the whole bandwidth having a bandwidth wider than 20 MHzas much as 2^(n) times is used for transmitting data without the nullchannel, and second region values of the bit sequence can indicate thatthe whole bandwidth having the bandwidth wider than 20 MHz as much as2^(n) times includes the one or more null channels.

The first region values of the bit sequence includes 1, 2, 3, and 4 and1, 2, 3, and 4 of the bit sequence can indicate 20 MHz, 40 MHz, 80 MHz,and 160 MHz, respectively.

If the radio frame is transmitted on a bandwidth of 80 MHz, the SIG Bfield can be transmitted via first to fourth channels each of whichcorresponds to a band of 20 MHz and SIG B field control information,which is transmitted via the first channel and the second channel, makesa pair with the third channel and the fourth channel and can berepeatedly transmitted via each of the pairs.

If the bandwidth information of the SIG A field indicates that the nullchannel is included in the whole bandwidth of 80 MHz, SIG B fieldcontrol information, which is transmitted via a channel rather than thenull channel among two channels making a pair, can indicate a locationof the null channel.

Information indicating the location of the null channel among the SIG Bfield control information can indicate that 242 tones corresponding to aspecific channel correspond to an empty resource region.

If the radio frame is transmitted on a bandwidth of 160 MHz, the SIG Bfield is transmitted via first to eighth channels each of whichcorresponds to a band of 20 MHz, SIG B field control information, whichis transmitted via the first channel, makes a first pair with the thirdchannel, the fifth channel, and the seventh channel and is repeatedlytransmitted via each of the channels, and SIG B field controlinformation, which is transmitted via the second channel, makes a secondpair with the fourth channel, the sixth channel, and the eighth channeland can be repeatedly transmitted via each of the channels.

If the bandwidth information of the SIG A field indicates that the nullchannel is included in the whole bandwidth of 160 MHz, SIG B fieldcontrol information, which is transmitted via a channel rather than thenull channel of a pair including the null channel among the first pairand the second pair, can indicate a location of the null channel.

Information indicating the location of the null channel among the SIG Bfield control information can indicate that 242 tones corresponding to aspecific channel correspond to an empty resource region.

If the whole bandwidth is equal to or wider than 80 MHz, the wholebandwidth can include a primary 20 MHz channel, a secondary 20 MHzchannel, and a secondary 40 MHz channel and the primary 20 MHz channelmay not be configured as the null channel.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, according to a different embodiment, amethod of receiving a signal, which is received by an STA (station)operating in a wireless LAN (WLAN) system using a multi user (MU)scheme, includes the steps of receiving a radio frame in which asignaling (SIG) field including control information and a data field fortransmitting data are included, and processing the received radio frame.In this case, the signaling field includes an SIG A field includingbandwidth information indicating the whole bandwidth having a bandwidthwider than 20 MHz as much as 2^(n) times and an SIG B field includinguser specific information and the bandwidth information of the SIG Afield can check whether or not the whole bandwidth includes one or more20 MHz bands (null channel) not used for transmitting data.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, according to a further differentembodiment, an STA (station) capable of operating in a wireless LAN(WLAN) system using a multi user (MU) scheme includes a processorconfigured to configure a radio frame in which a signaling (SIG) fieldincluding control information and a data field for transmitting data areincluded, wherein the signaling field is configured to include an SIG Afield including bandwidth information indicating the whole bandwidthhaving a bandwidth wider than 20 MHz as much as 2^(n) times and an SIG Bfield including user specific information, and a transceiver configuredto receive a radio frame from the processor and transmit the radio frameto one or more other STAs. In this case, the processor is configured tomake the bandwidth information of the SIG A field additionally indicatewhether or not the whole bandwidth includes one or more 20 MHz bands(null channel) not used for transmitting data.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, according to a further differentembodiment, an STA (station) capable of operating in a wireless LAN(WLAN) system using a multi user (MU) scheme includes a transceiverconfigured to receive a radio frame in which a signaling (SIG) fieldincluding control information and a data field for transmitting data areincluded, and a processor configured to process the radio frame receivedby the transceiver. In this case, the signaling field includes an SIG Afield including bandwidth information indicating the whole bandwidthhaving a bandwidth wider than 20 MHz as much as 2^(n) times and an SIG Bfield including user specific information and the processor isconfigured to check whether or not the whole bandwidth includes one ormore 20 MHz bands (null channel) not used for transmitting data via thebandwidth information of the SIG A field.

Advantageous Effects

According to the present disclosure, a station (STA) can efficientlytransmit a signal in a wireless communication system. Specifically, aresource allocation scheme can be performed efficiently for orthogonalfrequency division multiple access (OFDMA) or multi-user multiple inputmultiple output (MU-MIMO) in a future-generation wireless local areanetwork (WLAN) system conforming to institute of electrical andelectronics engineers (IEEE) 802.11ax among wireless communicationsystems.

It will be appreciated by persons skilled in the art that the effectsthat could be achieved with the present disclosure are not limited towhat has been particularly described hereinabove and the above and othereffects that the present disclosure could achieve will be more clearlyunderstood from the following detailed description.

DESCRIPTION OF DRAWINGS

FIG. 1 is a view illustrating an exemplary configuration of a WirelessLocal Area Network (WLAN) system.

FIG. 2 is a view illustrating another exemplary configuration of a WLANsystem.

FIG. 3 is a view illustrating an exemplary structure of a WLAN system.

FIGS. 4 to 8 are views illustrating exemplary frame structures in aninstitute of electrical and electronics engineers (IEEE) 802.11 system.

FIG. 9 is a view illustrating exemplary physical layer protocol dataunit (PPDU) formats that may be used in the present disclosure.

FIG. 10 is a view illustrating uplink multi-user (UL MU) transmissionapplicable to the present disclosure.

FIGS. 11 and 12 are views illustrating inefficiency of a legacy channelallocation scheme.

FIGS. 13 and 14 are views illustrating the concept of supporting anon-contiguous channel or a 60× MHz channel according to an embodimentof the present disclosure.

FIG. 15 is a view illustrating a resource allocation format to use anon-contiguous band or a 60× MHz band according to an embodiment of thepresent disclosure.

FIGS. 16 and 17 are views illustrating specific forms of the resourceallocation format illustrated in FIG. 15.

FIGS. 18 and 19 are exemplary views illustrating configuration of a nullindication as a bitmap according to an embodiment of the presentdisclosure.

FIGS. 20 and 22 are views illustrating a resource allocation method fora total bandwidth of 160 MHz according to an embodiment of the presentdisclosure.

FIG. 23 is an exemplary view illustrating a Null Bandwidth (BW) Presencefield according to an embodiment of the present disclosure.

FIGS. 24 and 25 are diagrams for explaining a structure for transmittingHE-SIG B in a band equal to or wider than 80 MHz according to oneembodiment of the present invention.

FIG. 26 is a block diagram illustrating exemplary configurations of anAccess Point (AP) (or Base Station (BS)) and a Station (STA) (or UserEquipment (UE)).

FIG. 27 is a view illustrating an exemplary structure of a processor inan AP or an STA.

BEST MODE Mode for Invention

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art.

Embodiments described hereinbelow are combinations of elements andfeatures of the present invention. The elements or features may beconsidered selective unless otherwise mentioned. Each element or featuremay be practiced without being combined with other elements or features.Further, an embodiment of the present invention may be constructed bycombining parts of the elements and/or features. Operation ordersdescribed in embodiments of the present invention may be rearranged.Some constructions of any one embodiment may be included in anotherembodiment and may be replaced with corresponding constructions ofanother embodiment.

Specific terms used in the embodiments of the present invention areprovided to aid in understanding of the present invention. Thesespecific terms may be replaced with other terms within the scope andspirit of the present invention.

In some cases, to prevent the concept of the present invention frombeing obscured, structures and apparatuses of the known art will beomitted, or will be shown in the form of a block diagram based on mainfunctions of each structure and apparatus. In addition, whereverpossible, the same reference numbers will be used throughout thedrawings and the specification to refer to the same or like parts.

The embodiments of the present invention can be supported by standarddocuments disclosed for at least one of wireless access systems,Institute of Electrical and Electronics Engineers (IEEE) 802, 3rdGeneration Partnership Project (3GPP), 3GPP Long Term Evolution (3GPPLTE), LTE-Advanced (LTE-A), and 3GPP2. Steps or parts that are notdescribed to clarify the technical features of the present invention canbe supported by those documents. Further, all terms as set forth hereincan be explained by the standard documents.

In the present disclosure, a terminology, each of which includes such anordinal number as 1st, 2nd and the like, may be used to describe variouscomponents. In doing so, the various components should be non-limited bythe corresponding terminologies, respectively. The terminologies areonly used for the purpose of discriminating one component from othercomponents. For example, a first configuration element can be referredto as a second configuration element, similarly, the secondconfiguration element can be referred to as the first configurationelement while not being deviated from the scope of right according tothe concept of the present specification.

In the present application, such a terminology as ‘comprise’, ‘include’and the like should be construed not as excluding existence of adifferent configuration element but as designating further existence ofa different configuration element. In this disclosure, such aterminology as ‘ . . . unit’, ‘ . . . part’ corresponds to a unit forprocessing at least one or more functions or operations. The unit can beimplemented by a combination of hardware and/or software.

FIG. 1 is a view illustrating an exemplary configuration of a WirelessLocal Area Network (WLAN) system.

As depicted in FIG. 1, a wireless local area network includes at leastone Basic Service Set (BSS). The BSS is a set of Stations (STA) capableof communicating with each other by successfully performingsynchronization.

The STA is a logical entity including a physical layer interface for aMedium Access Control (MAC) and wireless media. The STA includes anAccess Point (AP) and a Non-AP STA. A mobile terminal operated by a usercorresponds to the Non-AP STA among the STAs. If it is simply called anSTA, the STA may correspond to the Non-AP STA. The Non-AP STA can becalled such a different name as a terminal, a Wireless Transmit/ReceiveUnit (WTRU), User Equipment (UE), a Mobile Station (MS), a MobileTerminal, a Mobile Subscriber Unit, or the like.

And, the AP is an entity providing an STA associated to the AP with anaccess to a Distribution System (DS) via the wireless media. The AP canbe called a concentrated controller, a Base Station (BS), a Node-B, aBase Transceiver System (BTS), a site controller, or the like.

The BSS can be divided into an infrastructure BSS and an Independent BSS(IBSS).

The BSS depicted in FIG. 1 corresponds to the IBSS. The IBSS means theBSS not including an AP. Since the IBSS does not include the AP, anaccess to the DS is not permitted to the IBSS. Thus, the IBSS forms aself-contained network.

FIG. 2 is a view illustrating another exemplary configuration of a WLANsystem.

The BSS depicted in FIG. 2 corresponds to the infrastructure BSS. Theinfrastructure BSS includes at least one STA and an AP. Although aprinciple of a communication between non-AP STAs is to perform thecommunication via the AP, if a link is directly established between thenon-AP STAs, it is possible to directly communicate between the non-APSTAs.

As depicted in FIG. 2, a plurality of infrastructure BSSs can beconnected to each other via the DS. A plurality of the infrastructureBSSs connected through the DS is called an Extended Service Set (ESS).STAs included in the ESS can communicate with each other and a non-APSTA can move from one BSS to another BSS while seamlessly communicatingin an identical ESS.

The DS is a mechanism connecting a plurality of APs to each other andthe DS is not necessarily to be a network. If the DS is able to providea prescribed distribution service, there is no limit on a form of theDS. For instance, the DS may correspond to such a wireless network as amesh network or may correspond to a physical structure connecting APs toeach other.

FIG. 3 is a view illustrating an exemplary structure of a WLAN system.In FIG. 3, an example of an infrastructure BSS including a DS isdescribed.

Referring to an example of FIG. 3, ESS includes a BSS1 and BSS2. In aWLAN system, a station corresponds to a device operating according toMAC/PHY regulation of IEEE 802.11. A station includes an AP station anda non-AP station. In general, the non-AP station corresponds to such adevice directly handled by a user as a laptop computer, a mobile phone,and the like. In the example of FIG. 3, a station 1, a station 3, and astation 4 correspond to the non-AP station and a station 2 and a station5 correspond to the AP station.

In the following description, the non-AP station may be referred to as aterminal, a Wireless Transmit/Receive Unit (WTRU), a User Equipment(UE), a Mobile Station (MS), a mobile terminal, a Mobile SubscriberStation (MSS), and the like. And, the AP corresponds to a Base Station(BS), a Node-B, an evolved Node-B (eNB), a Base Transceiver System(BTS), a femto BS, and the like.

FIGS. 4 to 8 illustrate exemplary frame structures used in an Instituteof Electrical and Electronics Engineers (IEEE) 802.11 system.

An STA may receive a PLCP Protocol Data Unit (PPDU). A PPDU frame may beformatted to include a Short Training Field (STF), a Long Training Field(LTF), a SIGNAL (SIG) field, and a Data field. For example, a PPDU frameformat may be configured based on the type of the PPDU frame format.

For example, a non-High Throughput (non-HT) PPDU format may include onlya Legacy-STF (L-STF), a Legacy-LTF (L-LTF), a SIG field, and a Datafield.

The PPDU frame format type may be configured to be one of a HT-mixedformat PPDU and an HT-greenfield format PPDU. The above-described PPDUformat may further include an additional STF (or an STF of a differenttype), an additional LTF (or an LTF of a different type), and anadditional SIG field (or a SIG field of a different type) between theSIG field and the Data field.

Referring to FIG. 5, a Very High Throughput (VHT) PPDU format may beconfigured. The VHT PPDU format may also include an additional STF (oran STF of a different type), an additional LTF (or an LTF of a differenttype), and an additional SIG field (or a SIG field of a different type)between the SIG field and the Data field. More specifically, at leastone of a VHT-SIG-A field, a VHT-STF, a VHT-LTF, and a VHT SIG-B fieldmay further be included between an L-SIG field and the Data field in theVHT PPDU format.

An STF may be a signal used for Automatic Gain Control (AGC), diversityselection, accurate time synchronization, etc. The STF and the LTF maybe collectively referred to as a Physical Layer Convergence Protocol(PLCP) preamble, and the PLCP preamble may be a signal used forsynchronization and channel estimation of an OFDM physical layer.

Referring to FIG. 6, the SIG field may include a RATE field and a LENGTHfield. The RATE field may include information about modulation and acoding rate of data. The LENGTH field may include information about thelength of the data. Additionally, the SIG field may include parity bits,and SIG Tail bits.

The Data field may include a SERVICE field, a PLCP Service DATA Unit(PSDU), and PPDU TAIL bits. When needed, the Data field may also includepadding bits.

Referring to FIG. 7, a part of bits of the SERVICE field may be used forsynchronization of a descrambler in a receiver, and another part of thebits of the SERVICE field may be reserved. The PSDU may correspond to aMAC Protocol Data Unit (PDU) defined at the MAC layer and include datagenerated/used by a higher layer. The PPDU TAIL bits may be used toreturn an encoder to a zero state. The padding bits may be used to matchthe length of the Data field to a predetermined unit.

As described before, for example, the VHT PPDU format may include anadditional STF (or an STF of a different type), an additional LTF (or anLTF of a different type), and an additional SIG field (or a SIG field ofa different type). The L-STF, the L-LTF, and the L-SIG may be a part fornon-VHT in the VHT PPDU, and the VHT-SIG-A, the VHT-STF, the VHT-LTF,and the VHT-SIG-B may be a part for VHT. In other words, an area fornon-VHT fields and an area for VHT fields may be separately defined inthe VHT PPDU. For example, the VHT-SIG-A may include information forinterpreting the VHT PPDU.

Referring to FIG. 8, for example, the VHT-SIG-A may include VHT SIG-A1(FIG. 8(a)) and VHT SIG-A2 (FIG. 8(b)). Each of the VHT SIG-A1 and theVHT SIG-A2 may have 24 data bits, and the VHT-SIG A1 may precede theVHT-SIG A2. The VHT-SIG-A1 may include a Bandwidth (BW) field, a SpaceTime Block Coding (STBC) field, a Group Identifier (ID) field, a Numberof Space-Time Streams (NSTS)/Partial Association ID (Partial AID) field,a TXOP_PS_NOT_ALLOWED field, and a Reserved field. The VHT SIG-A2 mayinclude a Short Guard Interval (GI) field, a Short GI NSYMDisambiguation field, a Single User (SU)/Multi-User (MU)[0] Codingfield, a Low Density Parity Check (LDPC) Extra OFDM Symbol field, an SUVHT-Modulation Coding Scheme (MCS)/MU[1-3] Coding field, a Beamformedfield, a Cyclic Redundancy Check (CRC), a Tail, and a Reserved field.Information about the VHT PPDU may be acquired from the VHT SIG-A1 andthe VHT SIG-A2.

FIG. 9 is a view illustrating exemplary physical layer protocol dataunit (PPDU) formats that may be used in the present disclosure.

As described before, various PPDU formats are available. For example, anew PPDU format may be provided. A PPDU may include L-STF, L-LTF, L-SIG,and DATA fields. For example, the PPDU frame may further include HE-SIGA, HE-STF, HE-LTF, and HE-SIG B fields. The HE-SIG A field may include,for example, common information. For example, the common information mayinclude Bandwidth, Guard Interval (GI), Length, BSS Color, and so on.For example, an L part (L-STF, L-LTF, and L-SIG) may be transmitted in aSingle Frequency Network (SFN) mode on a 20-MHz basis in the frequencydomain. For example, like the L part, the HE-SIG A field may betransmitted in the SFN mode on a 20-MHz basis. For example, if a channelhas a bandwidth larger than 20 MHz, the L part and the HE-SIG A fieldmay be duplicated on a 20-MHz basis and then transmitted. The HE SIG-Bfield may provide user-specific information. For example, theuser-specific information may include an STA AID, resource allocationinformation (e.g., an allocation size), an MCS, N_(sts), coding, STBC,TXBF, and so on. Further, the HE SIG-B field may be transmitted across atotal bandwidth.

For example, referring to (b) of FIG. 9, a PPDU may be transmitted in an80-MHz band. The L part and the HE-SIG A field may be duplicated on a20-MHz basis and then transmitted, and the HE-SIG B field may betransmitted across the total 80-MHz band. However, the transmissionscheme may be purely exemplary, not limited to the above embodiment.

FIG. 10 is a view illustrating uplink multi-user (UL MU) transmissionapplicable to the present disclosure.

As described above, the AP may acquire a TXOP to access a medium, andtransmit a signal by occupying the medium through contention. Referringto FIG. 10, the AP STA may transmit a trigger frame to a plurality ofSTAs to perform UL MU transmission. In this case, the trigger frame mayinclude, for example, information about a resource allocation positionand size, IDs of the STAs, MCS, and MU type (=MIMO, OFDMA) as UL MUallocation information. That is, the trigger frame transmitted by the APSTA to the plurality of STAs may be a frame allowing the plurality ofSTAs to perform UL data transmissions.

The plurality of STAs may transmit data to the AP after an SIFS elapsesbased on a format indicated by the trigger frame. The AP may then sendACK/NACK information to the STAs, and thus the STAs may perform UL MUtransmissions.

FIGS. 11 and 12 are views illustrating inefficiency of a legacy channelallocation scheme.

Referring to FIGS. 11 and 12, only when a contiguous channel including aprimary channel is idle, a legacy VHT STA uses the contiguous channel.Specifically, FIG. 11 illustrates data transmission on a 20-MHz primarychannel, when the primary channel is idle for a predetermined time, andFIG. 12 illustrates data transmission on a 40-MHz channel being acombination of a primary channel and a 20-MHz secondary channel,Secondary 20, when the primary channel and the 20-MHz secondary channel,Secondary 20 contiguous to the primary channel are idle for apredetermined time.

However, if channels are used in the above manner, another secondarychannel, Secondary 40 is not used, thereby causing inefficiency, asillustrated in FIG. 11. Similarly in FIG. 12, a channel withoutinterference in the secondary channel, Secondary 40 is not used, thusdecreasing efficiency.

FIGS. 13 and 14 are views illustrating the concept of supporting anon-contiguous channel or a 60× MHz channel according to an embodimentof the present disclosure.

To solve the problem described with reference to FIGS. 11 and 12, asystem which supports 60× MHz (x is a natural number) as illustrated inFIG. 13 or enables data transmission on a non-contiguous channel asillustrated in FIG. 14 is proposed in an embodiment of the presentdisclosure.

Specifically, FIG. 13 illustrates an example of configuring a 60-MHzchannel with both the primary channel and the secondary channel,Secondary 40, except a busy channel part in the situation of FIG. 11. Ifa total bandwidth (BW) is 160 MHz, it is proposed that a channel of upto 120 (60×2) MHz is supported, compared to the legacy technology.

FIG. 14 illustrates a method for transmitting data on a non-contiguouschannel except a channel with interference in the situation illustratedin the lower part of FIG. 12. That is, it is proposed that resources areused flexibly except only a channel unavailable due to interference orthe like, compared to the legacy technology in which only a contiguouschannel within a total BW is used.

In summary, the legacy system provides only brief information about 20,40, 80, and 160 (or 80+80)-MHz units among contiguous BWs in a SIG field(BW field). However, an embodiment of the present disclosure proposes amethod for indicating use of a 60× MHz contiguous BW or a non-contiguousband, as described above.

FIG. 15 is a view illustrating a resource allocation format to use anon-contiguous band or a 60× MHz band according to an embodiment of thepresent disclosure.

As shown in FIG. 15, when a frame is transmitted, an STA can includeinformation on an unused bandwidth and information on a null indicator(e.g., null bandwidth/channel/sub-channel information or non-contiguousbandwidth/channel/subchannel information) in a HE-SIG field. It ispreferable to include the information in the HE-SIG field only when a BWcorresponds to 80 MHz or 160 (or 80+80) MHz.

In particular, the present invention proposes that the HE-SIG fieldincludes bandwidth information indicating whether or not the wholebandwidth corresponds to 20, 40, 80, or 160 (or 80+80) MHz andinformation on a null indicator indicating a channel region not used fortransmitting data among the whole bandwidth.

Information on currently used contiguous bandwidths or non-contiguousbandwidths can be included in the HE-SIG field instead of a nullsubchannel indicator. The information on the contiguous ornon-contiguous bandwidths may indicate information on a practically usedbandwidth or a subchannel Preferably, a unit may correspond to 20 MHz ora multiple of 20 MHz (e.g., 40 MHz, 80 MHz, . . . ).

Preferably, the HE-SIG field may correspond to a HE-SIG A. The HE-SIG Acan be indicated by a common part of a HE-SIG B, L-SIG corresponding toa previous part of the HE-SIG A, phase rotation, or the like.

FIGS. 16 and 17 are views illustrating specific forms of the resourceallocation format illustrated in FIG. 15.

As described before, an 11ax radio frame may include HE-SIG A and HE-SIGB as HE-SIG fields. In general, HE-SIG A may include common controlinformation for a plurality of channels (users), and HE-SIG B mayinclude information specific to each of the plurality of channels (orusers). Further, HE-SIG B may be configured so that a predetermined partof HE-SIG B includes channel-common (user-common) information, and theremaining part of HE-SIG B includes channel-specific (user-specific)information.

If total BW information and null indication information are transmittedaccording to the foregoing embodiment, both the total BW information andthe null indication information may be included in HE-SIG A, asillustrated in FIG. 16. Alternatively or additionally, as illustrated inFIG. 17, the total BW information may be included in HE-SIG A, and thenull indication information may be included in HE-SIG B.

Now, a description will be given of a case in which a null indication isconfigured as a bitmap and a case in which a null indication isconfigured as an index indicating a channel combination, as specificexamples of the foregoing embodiment.

Bitmap-Type Null Indication

FIGS. 18 and 19 are exemplary views illustrating configuration of a nullindication as a bitmap according to an embodiment of the presentdisclosure.

The null indication may be configured as a bitmap or an index, andincluded and transmitted in HE-SIG A or HE-SIG B, as described above. Ifthe null indication is configured in the form of a bitmap, each bit ofthe bitmap may be mapped to a 20-MHz BW. In the bitmap, a bit set to 1may indicate a non-allocated subband and a bit set to 0 may indicate anallocated subband in the example of FIG. 18. That is, a bitmap of 0100may indicate that only the second 20-MHz channel is not used for datatransmission, and the remaining first, third, and fourth 20-MHz channelsare used for data transmission, among the 20-MHz channels in FIG. 18.

The bitmap may provide actually used BW information, instead of null BWinformation. Then, a bit is set to 1 to indicate an actually usedchannel and to 0 to indicate an unused channel in the bitmap. That is,although the null indication bitmap indicates null BWs, the bitmap maybe configured to provide non-contiguous BW information. In other words,the bitmap may indicate BWs allocated for data transmission in FIG. 19,unlike FIG. 18. For example, the non-contiguous BW information may berepresented as 1011 in the above example. FIG. 10 describesnon-contiguous BW information, and although the term, null BWinformation is used for distinction, it may also be regarded as a kindof null indication.

For 80 MHz, the null indication may be configured as a 4-bit bitmap,whereas for 160 (or 80+80) MHz, the null indication may be configured asan 8-bit bitmap.

FIGS. 20 to 22 are views illustrating a resource allocation method for atotal BW of 160 MHz according to an embodiment of the presentdisclosure.

For 160 (or 80+80) MHz, null BWs may be indicated on a 40-MHz basis, asillustrated in FIG. 20. In this case, a 4-bit bitmap may be configuredfor 160 MHz, as for 80 MHz.

In the above case, however, a partial band of a secondary channel,Secondary 40 may not be used, as illustrated in FIG. 20.

FIG. 21 illustrates an example of indicating null BWs on a 20-MHz basisfor 160 (0r 80+80) MHz.

If all or part of the secondary channel, Secondary 40 has interference,none of the secondary channel, Secondary 40 is not used in the aboveexample.

Unlike FIG. 21, if part of the secondary channel, Secondary 40 is used,a null BW bitmap may be configured as 00000100 in FIG. 22.

Similar to 11ac, if a primary channel concept is used, a bitmap can beconfigured by the remaining bits except primary channels. For example, abitmap is configured by 3 bits in 80 MHz and each of the 3 bitsindicates whether or not a corresponding secondary channel is included.Table 1 in the following illustrates an example that a bitmap isconfigured for a secondary channel except a primary channel.

TABLE 1 Bandwidth index bitmap 000: 20MHz (primary) 100: 40MHz(Contiguous, Primary + Secondary 20) 010: 40MHz (Contiguous, Primary +1st sub-CH of Seondary 40) 001: 40MHz (Non-contiguous, Primary + 2ndsub-CH of Secondary 40) 110: 60MHz (Contiguous, Primary+ Secondary 20 +1st sub-CH of Secondary 40) 011: 60MHz (Contiguous, Primary+ Secondary40) 101: 60MHz (Non-contiguous, Primary + Secondary 20 + 2nd sub-CH ofSecondary 40) 111: 80MHz (Contiguous)

A similar bitmap may be configured for 160 (or 80+80) MHz. That is, a7-bit bitmap may correspond to respective secondary channels, Secondary20, Secondary 40, and Secondary 80, and may indicate which secondarychannel is used along with a primary channel, as follows.

TABLE 2 0000000: 2 MHz (primary) 1000000: 40MHz (Contiguous, Primary +Secondary 20) 0100000: 40MHz (Contiguous, Primary + 1st sub-CH ofSeondary 40) 0010000: 40MHz (Non-contiguous, Primary + 2nd sub-CH ofSecondary 40) 1100000: 60MHz (Contiguous, Primary+ Secondary 20 + 1stsub-CH of Secondary 40) 0110000: 60MHz (Contiguous, Primary+ Secondary40) 1010000: 60MHz (Non-contiguous, Primary + Secondary 20 + 2nd sub-CHof Secondary 40) 1110000: 80MHz (Contiguous) ..... 1111111: 160MHz or(80+80) MHz

3 bits may be used to indicate BW indexes, and additional informationabout contiguous/non-contiguous channels may be represented as follows,inclusive of legacy BW information (20/40/80/160 MHz).

TABLE 3 Bandwidth index (3bits) 0: 20MHz (primary) 1: 40MHz (Contiguous,Primary + Secondary 20) 2: 40MHz (Contiguous, Primary + 1st sub-CH ofSeondary 40) 3: 40MHz (Non-contiguous, Primary + 2nd sub-CH of Secondary40) 4: 60MHz (Contiguous, Primary+ Secondary 20 + 1st sub-CH ofSecondary 40) 5: 60MHz (Contiguous, Primary+ Secondary 40) 6: 80MHz(Contiguous) 7: 160MHz or 80+80 MHz

The example above illustrates an example that 60 MHz non-contiguous isomitted. Instead, legacy 160 MHz or 80+80 MHz is included.

If 60 MHz non-contiguous is not omitted, it may have Table 4 describedin the following.

TABLE 4 Bandwidth index (4bits) 0: 20MHz (primary) 1: 40MHz (Contiguous,Primary + Secondary 20) 2: 40MHz (Contiguous, Primary + 1st sub-CH ofSeondary 40) 3: 40MHz (Non-contiguous, Primary + 2nd sub-CH of Secondary40) 4: 60MHz (Contiguous, Primary+ Secondary 20 + 1st sub-CH ofSecondary 40) 5: 60MHz (Contiguous, Primary+ Secondary 40) 6: 60MHz(Non-contiguous, Primary+Secondary 20 + 2nd sub-CH of Secodnary 40) 7:80MHz (Contiguous) 8: 160MHz or 80+80 MHz 9-15: Reserved

The meaning of the secondary channel shown in Table 1 can be changed asfollows.

TABLE 5 Bandwidth index (3bits) 0: 20MHz (primary) 1: 40MHz (PrimaryCH + 1st Secondary CH) 2: 40MHz (Primary CH + 2nd Secondary CH) 3: 40MHz(Primary CH + 3rd Secondary CH) 4: 60MHz (Primary CH + 1st SecondaryCH + 2nd Secondary CH) 5: 60MHz (Primary CH + 2nd Secondary CH + 3rdSecondary CH) 6: 60MHz (Primary CH + 1st Secondary CH + 3rd SecondaryCH) 7: 80MHz (Contiguous)

The meaning of the secondary channel shown in Table 3 can be changed asfollows.

TABLE 6 Bandwidth index (3bits) 0: 20MHz (primary) 1: 40MHz (PrimaryCH + 1st Secondary CH) 2: 40MHz (Primary CH + 2nd Secondary CH) 3: 40MHz(Primary CH + 3rd Secondary CH) 4: 60MHz (Primary CH + 1st SecondaryCH + 2nd Secondary CH) 5: 60MHz (Primary CH + 2nd Secondary CH + 3rdSecondary CH) 6: 80MHz 7: 160MHz or 80+80 MHz

The meaning of the secondary channel shown in Table 3 can also bechanged as follows.

TABLE 7 Bandwidth index (4bits) 0: 20MHz (primary) 1: 40MHz (PrimaryCH + 1st Secondary CH) 2: 40MHz (Primary CH + 2nd Secondary CH) 3: 40MHz(Primary CH + 3rd Secondary CH) 4: 60MHz (Primary CH + 1st SecondaryCH + 2nd Secondary CH) 5: 60MHz (Primary CH + 2nd Secondary CH + 3rdSecondary CH) 6: 60MHz (Primary CH + 1st Secondary CH + 3rd SecondaryCH) 7: 80MHz (Contiguous) 8: 160MHz or 80+80 MHz 9-15: Reserved

Meanwhile, if a null bandwidth is not included in 80 MHz or 160 MHz,null bandwidth information may become unnecessary information. Hence,according to one embodiment of the present invention, it may be able toselectively include the null bandwidth information by indicating whetheror not the null bandwidth information is included. In particular, it maybe able to make the null bandwidth information (e.g., bitmap) to beincluded in the HE-SIG field only when a null bandwidth presence is setto 1.

FIG. 23 is an exemplary view illustrating a Null Bandwidth (BW) Presencefield according to an embodiment of the present disclosure.

When a BW field is included in HE-SIG A, if a BW corresponds to 80 MHzor 160 MHz, as shown in FIG. 22, the null bandwidth information can betransmitted in a manner of being included in HE-SIG B. And, as shown inFIG. 22, if null bandwidth presence is included, the null bandwidthinformation can be included or omitted depending on a value of the nullbandwidth presence.

More preferably, the value of the null bandwidth presence is included inthe HE-SIG A via a bitmap indicating the whole bandwidth. If the nullbandwidth presence is set to 1, the null bandwidth information(information on whether or not a subchannel is used) can be included inthe HE-SIG B (e.g., SIG B common part).

Index-Type Null Indication

As described before, a null BW bitmap is an example of null subbandinformation. The null subband information may be indicated by a formother than a null BW bitmap.

The following table is an example of indicating null subband informationin 80 MHz by an index.

TABLE 8 1st 2nd 3rd Index P-CH S-CH S-CH S-CH Notes 1 ∘ ∘ ∘ x 60 MHz 2 ∘∘ x ∘ 3 ∘ x ∘ ∘ 4 ∘ x ∘ x Non- 5 ∘ x x ∘ contiguous 40 MHz

In the example of [Table 8], o indicates allocation of a band, and xindicates non-allocation of a band.

Index 1 indicates a contiguous 60-MHz channel including a primarychannel Indexes 2 and 3 indicate non-contiguous 60-MHz BWs, and Indexes4 and 5 indicate non-contiguous 40-MHz BWs.

The following table illustrates another example. A column representingthe primary channel is interposed between columns representing thesecondary channels, Secondary 20 and Secondary 40.

TABLE 9 Secondary Primary Secondary Secondary Index 20 CH 40 40 Notes 1∘ ∘ ∘ x 60 MHz 2 ∘ ∘ x ∘ 3 x ∘ ∘ ∘ 4 x ∘ ∘ x Non- 5 x ∘ x ∘ contiguous40 MHz

It is able to transmit a frame without including a primary CH. A tablein the following illustrates an example of including the primary CH.

TABLE 10 1st 2nd 3rd Index P-CH S-CH S-CH S-CH Notes 1 ∘ ∘ ∘ x 60 MHz 2∘ ∘ x ∘ 60 MHz 3 ∘ x ∘ ∘ 60 MHz 4 x ∘ ∘ ∘ 60 MHz 5 ∘ x ∘ x 40 MHz 6 ∘ xx ∘ 40 MHz 7 x ∘ ∘ x 40 MHz 8 x ∘ x ∘ 40 MHz 9 x x ∘ ∘ 40 MHz 10 x ∘ x x20 MHz 11 x x ∘ x 20 MHz 12 x x x ∘ 20 MHz

A method similar to the abovementioned method can be defined in 160 MHz.A table in the following illustrates an example of indicating a nullbandwidth in a unit of 40 MHz in 160 MHz.

TABLE 11 P-CH, 1st 2nd & 3rd 4th & 5th 6th & 7th Index S-CH S-CH S-CHS-CH Notes 1 ∘ ∘ ∘ x 120 MHz 2 ∘ ∘ x ∘ 3 ∘ x ∘ ∘ 4 ∘ x ∘ x Non- 5 ∘ x x∘ contiguous 80 MHz

It is able to transmit a frame without including a primary CH. A tablein the following illustrates an example of including the primary CH.

TABLE 12 P-CH, 1st 2nd & 3rd 4th & 5th 6th & 7th Index S-CH S-CH S-CHS-CH Notes 1 ∘ ∘ ∘ x 120 MHz  2 ∘ ∘ x ∘ 3 ∘ x ∘ ∘ 4 x ∘ ∘ ∘ 5 ∘ x ∘ x 80MHz 6 ∘ x x ∘ 7 x ∘ ∘ x 8 x ∘ x ∘ 9 x x ∘ ∘ 10 x ∘ x x 40 MHz 11 x x ∘ x12 x x x ∘

A table in the following illustrates an example of indicating allocationinformation of a bandwidth in a unit of 20 MHz in 160 MHz.

TABLE 13 1st S- 2nd S- 3rd S- 4th S- 5th S- 6th S- 7th S- Index P-CH, CHCH CH CH CH CH CH Notes 1 ∘ ∘ ∘ ∘ ∘ ∘ ∘ x 140 2 ∘ ∘ ∘ ∘ ∘ ∘ x ∘ 3 ∘ ∘ ∘∘ ∘ x ∘ ∘ 4 ∘ ∘ ∘ ∘ x ∘ ∘ ∘ 5 ∘ ∘ ∘ x ∘ ∘ ∘ ∘ 6 ∘ ∘ x ∘ ∘ ∘ ∘ x 7 ∘ x ∘∘ ∘ ∘ ∘ ∘ 8 ∘ ∘ ∘ ∘ ∘ ∘ x x 120 9 ∘ ∘ ∘ ∘ ∘ x ∘ x 10 ∘ ∘ ∘ ∘ x ∘ ∘ x 11∘ ∘ ∘ x ∘ ∘ ∘ x 12 ∘ ∘ x ∘ ∘ ∘ ∘ x 13 ∘ x ∘ ∘ ∘ ∘ ∘ x 14 ∘ ∘ ∘ ∘ ∘ x x x100 MHz 15 ∘ ∘ ∘ ∘ x ∘ x x 16 ∘ ∘ ∘ x ∘ ∘ x x 17 ∘ ∘ x ∘ ∘ ∘ x x . . . .. . . . . . . . . . . . . . . . . . . . . . .

Null subband information (non-contiguous BW information) can be usedtogether with a legacy BW index.

TABLE 14 BW Index 1 20 MHz 2 40 MHz 3 80 MHz 4 160 or (80 + 80) MHz 1st2nd 3rd P-CH S-CH S-CH S-CH Notes 5 ∘ ∘ ∘ x 60 MHz 6 ∘ ∘ x ∘ 7 ∘ x ∘ ∘ 8∘ x ∘ x 40 MHz 9 ∘ x x ∘ P-CH, 2nd & 3rd 4th & 5th 6th & 7th 1st S-CHS-CH S-CH S-CH Notes 10 ∘ ∘ ∘ x 120 MHz  11 ∘ ∘ x ∘ 12 ∘ x ∘ ∘ 13 ∘ x ∘x 80 MHz 14 ∘ x x ∘

In the above example, BW information indicates inclusion of the primarychannel all the time. In 160 MHz, a subband unit is 40 MHz. Variouscombinations may be produced from these indexes.

(1) Primary channel included & basic subband unit=40 MHz in 160MHz->indexes are configured as illustrated in [Table 14].

(2) Primary channel included & basic subband unit=20 MHz in 160 MHz

(3) Primary channel not included & basic subband unit=40 MHz in 160 MHz

(4) Primary channel not included & basic subband unit=20 MHz in 160 MHz

In the above example, subband use/non-use information (e.g., null BWinformation/non-contiguous subband information, or non-allocated subbandindication information) is provided for each 20-MHz unit in 80 MHz, andeach 40-MHz or 20-MHz unit in 160 MHz. The unit may be referred to as adifferent term or form corresponding to the same size.

[Table 15] below describes an exemplary time-frequency frame structurein an 11ax system.

TABLE 15 < Example of time-frequency frame structure in 11ax> FFT size(4-times extension from existing WiFi numerology): 256FFT for 20MHz,512FFT for 40MHz, 1024FFT for 80MHz, 2048FFT for contiguous 160MHz oreach 1024FFT for non-contiguous 160MHz BW Subcarrier spacing: 78.125kHz(¼ of existing WiFi numerology) IDFT/DFT length: 3.2 μs * 4 = 12.8 μsOFDM symbol length: IDFT/DFT length + GI

In the 11ax frame structure, a single basic resource unit configured by242 tones can be configured in 20 MHz. Two basic resource units and fourbasic resource units can be configured in 40 MHz and 80 MHz,respectively. In this case, 20 MHz can be indicated in a manner of beingreplaced with a resource unit configured by 242 tones. 40 MHz can beindicated in a manner of being replaced with 2 contiguous resource unitseach of which is configured by 242 tones (24 tone resource unit*2=40MHz). In this case, the resource units may become identical to theaforementioned information indicating whether or not a subband is used.For example, if a resource unit is represented by a bitmap, the resourceunit is configured by a bitmap of 4 bits in 80 MHz. In 140 MHz, if abasic null resource unit has a size of 20 MHz (242 tone resourceunit*2), the basic null resource unit is configured by a bitmap of 4-bitsize. If the basic null resource unit has a size of 20 MHz (242 toneresource unit), the basic null resource unit is configured by a bitmapof 16-bit size. In case of using an index, the abovementioned definitioncan be similarly defined.

A table in the following illustrates a different example of anon-contiguous bandwidth information format.

TABLE 16 Bandwidth index (4 bits, B4B3B2B1) MSB 1bit(b4): indicateswhether the BW is 80MHz BW or not. If (b4==1) { // 80 MHz B3b2b1: eachbit is mapped to each of secondary channel. B3 is mapped to a firstsecondary channel, B2 is mapped to a second secondary channel, and B1 ismapped to a third secondary channel. For example, 010 indicate that aprimary channel and a secondary channel are used. } else { // b4==0,indicates a different bandwidth except 80MHz. B3B2B1 //(includes aprimary channel) 000: 20MHz BW 001: 40MHz BW 010: 160MHz BW or 80 +80MHz BW 011 ~ 111: reserved }

A table in the following illustrates an example of supporting partialcontiguous or non-contiguous channel boding in 160 MHz using theremaining reserved bits.

TABLE 17 Bandwidth index (4 bits, B4B3B2B1) MSB 1bit(b4): indicateswhether it is 80MHz BW or not. If (b4==1) { // 80MHz, B3b2b1: each bitis mapped to each of secondary channels. B3 is mapped to a firstsecondary channel secondary channel (e.g., secondary 20), B2 is mappedto a second secondary channel (e.g., 1^(st) 20 of Secondary 40), and B1is mapped to the third secondary channel (e.g., 2^(nd) 20 of Secondary40). Naturally, the mapping order can be changed. For example, 010indicates that a primary channel and a secondary channel are used. }else { // b4==0, indicates a different bandwidth except 80MHz. Abandwidth equal to or wider than 80MHz corresponds to a bandwidthincluding primary 80. B3B2B1 //(includes a primary channel) 000: 20MHzBW 001: 40MHz BW 010: 160MHz BW or 80 + 80MHz BW 011: 100MHz(Contiguous, Primary 80 + 1^(st) secondary CH of secondary 80) 100:120MHz (Contiguous, Primary 80 + 1^(st) and 2^(nd) secondary CHs ofsecondary 80) 101: 120MHz (Non-contiguous, Primary 80 + 3^(rd) and4^(th) secondary CHs of secondary 80) 110: 140MHz (Contiguous, Primary80 + 1^(st), 2^(nd) ,and 3^(rd) secondary CHs of secondary 80) 111:140MHz (Non-contiguous, Primary 80 + 1^(st), 3^(rd) , and 4^(th)secondary CHs of secondary 80) }

Non-contiguous bandwidth information can be transmitted in a manner ofbeing included in L-SIG In this case, it is able to obtain a combininggain from HE-SIG A.

TABLE 18 Bandwidth index (4 bits, B4B3B2B1) MSB 1bit(b4): indicatesinformation on a BW equal to or narrower than 80MHz and subchannels. If(b4==1) { // contiguous/non-contiguous BWs<=80MHz, B3b2b1: Each bit ismapped to each of secondary channels. B3 is mapped to a first secondarychannel secondary channel (e.g., Secondary 20), B2 is mapped to a secondsecondary channel (e.g., 1st 20 of Secondary 40), and B1 is mapped to athird secondary channel (e.g., 2nd 20 of Secondary 40). Naturally, themapping order can be changed. For example, 010 indicate that a primarychannel and a secondary channel are used. } else { // b4==0 , Contiguous/ non-contiguous BWs > 80MHz indicates a different bandwidth except80MHz. A bandwidth equal to or wider than 80MHz corresponds to abandwidth including primary 80. B3B2B1 //(includes a primary channel)000: 160MHz BW or 80 + 80MHz BW 001: 100MHz (Contiguous, Primary 80 +1st secondary CH of secondary 80) 010: 120MHz (Contiguous, Primary 80 +1st and 2nd secondary CHs of secondary 80) 011: 120MHz (Non-contiguous,Primary 80 + 3rd and 4th secondary CHs of secondary 80) 100: 120MHz(Non-contiguous, Primary 80 + 2nd and 3rd secondary CHs of secondary 80)101: 140MHz (Contiguous, Primary 80 + 1st, 2nd ,and 3rd secondary CHs ofsecondary 80) 110: 140MHz (Contiguous, Primary 80 + 1st, 2nd ,and 4thsecondary CHs of secondary 80) 111: 140MHz (Non-contiguous, Primary 80 +1st, 3rd , and 4th secondary CHs of secondary 80) }

A combination of bandwidths equal to or wider than 80 MHz can beexpressed in a manner of being different from the abovementionedcombination.

A table in the following illustrates a further different example forcontiguous/non-contiguous BWs.

TABLE 19 * Bandwidth index (4 bits, b4b3b2b1) * MSB 1bit (b4): indicateswhether a BW corresponds to a BW equal to or narrower than 80MHz (e.g.,20MHz, 40MHz) or a BW of 160MHz using information on subchannels. - ifb4 corresponds to 0, it indicates a BW equal to or narrower than 80MHz(i.e.., 20MHz, 40MHz). - if b4 corresponds to 1, , it indicates a BW of160MHz. * If (b4 == 0) { // contiguous/non-contiguous BWs<=80MHz,B3b2b1: Each bit is mapped to each of secondary channels. B3 is mappedto a first secondary channel secondary channel (e.g., Secondary 20), B2is mapped to a second secondary channel (e.g., 1st 20 of Secondary 40),and B1 is mapped to a third secondary channel (e.g., 2nd 20 of Secondary40). Naturally, the mapping order can be changed. For example, 010indicate that a primary channel and a secondary channel are used. If allbits are 0 (i.e., b3b2b1=000), it indicates a BW of 20MHz. If a bit(i.e., B3 corresponding to a secondary channel of 20MHz) correspondingto a secondary channel belonging to primary 40 is set to 1 (i.e.,b3b2b1=100), it indicates a BW of 40MHz. The rest of cases indicate a BWof 80MHz. If bits indicate a BW of 80MHz, contiguous/non-contiguouschannels (i.e., contiguous/non-contiguous channels except a channelindicated by a BW of 40MHz, contiguous/non-contiguous channels having asize of 60MHz) exist in 80MHz. } else { // b4==1 , indicates a BW of160MHz. In 160MHz, Contiguous / non-contiguous may exist. B3B2B1: whenthe remaining secondary channels except primary 40 are bundled in a unitof 40MHz in 160MHz(or 80+80MHz), each bit corresponds to each ofsecondary channels having a size of 40MHz. For example, B3 indicates theremaining secondary channels (i.e., secondary 40) except primary 40belonging to primary 80. B2 indicates a first secondary channel in aunit of 40MHz in secondary 80 and B1 indicates a second secondarychannel in a unit of 40MHz in secondary 80. In the abovementionedexample, assume that transmission is always performed together withprimary 40. }

A table in the following illustrates a further different example forcontiguous/non-contiguous BWs.

TABLE 20 ? Bandwidth index (3 bits, b0b1b2) ? MSB 1bit (b0): indicateswhether a BW corresponds to a BW equal to or narrower than 80MHz (e.g.,20MHz, 40MHz) or a BW of 160MHz using information on subchannels. - ifb0 corresponds to 0, it indicates a BW equal to or narrower than 80MHz(i.e.., 20MHz, 40MHz). - if b0 corresponds to 1, it indicates a BW of160MHz. ? If (b0 == 0) { // contiguous/non-contiguous BWs<=80MHz, b1b2:00 indicates a BW of 20MHz. 01 indicates a BW of 40MHz. 10 indicates aBW of contiguous 80MHz. In particular, all of 80MHz are used fortransmission. 11 indicates channel boding in a BW of 80MHz. Inparticular, 11 indicate that a primary channel (20MHz) and a secondarychannel (40Mhz) are used in 80MHz in a manner of being bonded. } else {// b0==1 , indicates a BW of 160MHz. In 160MHz, channels may exist in amanner of being bonded. B1b2: 00 indicates all of 160MHz (or 80+80MHz)are used (i.e., contiguous 160MHz channel or non-contiguous 80+80MHzchannel). 01 indicates that a primary channel of 20MHz and a secondarychannel of 80MHz are used in 160MHz. 10 indicates that a primary channelof 40MHz and a secondary channel of 40MHz are used. 11 indicate that aprimary channel of 20MHz, a secondary channel of 40MHz, and a secondarychannel of 80MHz are used. }

A table in the following illustrates a further different example forcontiguous/non-contiguous BWs.

TABLE 21 * Bandwidth index (3 bits, b0b1b2) 000 indicates a BW of 20MHz.001 indicates a BW of 40MHz. 010 indicates a contiguous BW of 80MHz. Inparticular, all of 80MHz are used for transmission. 011 indicateschannel boding in a BW of 80MHz. In particular, 011 indicates thataprimary channel of 20MHz and a secondary channel of 40MHz are used in80MHz in a manner of being bonded. 100 indicate that all of 160MHz (or80+80MHz) are used (i.e., contiguous 160MHz channel or non-contiguous80+80MHz channel). 101 indicate that a primary 20MHz and a secondary80MHz are used in 160MHz. 110 indicate that a primary 40MHz and asecondary 80MHz are used. 111 indicate that a primary 20MHz, a secondary40 MHz and a secondary 80MHz are used. If b0 corresponds to 0, theabovementioned example indicates a BW equal to or narrower than 80MHz(i.e., 20MHz, 40MHz). In a BW of 80MHz, subchannels can be used in amanner of being bonded. If the b0 corresponds to 1, it indicates a PPDUtransmission BW of 160MHz. It may use channels bycontiguously/non-contiguously bonding the channels. }

In the examples above, when the null bandwidth information (ornon-contiguous channel information) is indicated by a bitmap in a unitof 20 MHz, a bitmap of 4 bits is configured in 80 MHz and a bitmap of 8bits is configured in 160 MHz. If a primary channel is excluded, abitmap of 3 bits is configured in 80 MHz and a bitmap of 7 bits isconfigured in 160 MHz. When a bitmap is configured in a unit of 40 MHzin 160 MHz, a bitmap of 3 bits (a primary channel is not included in thebitmap) or a bitmap of 4 bits can be configured depending on whether ornot a primary channel is included. As shown in Table 17, if primarychannel information (information indicating whether or not a BW includesprimary 20 or primary 40) is included in HE-SIG A and detail nullbandwidth information (or non-contiguous channel information) isincluded in HE-SIG B, information included in the SIG B can be reduced.

A table 22 in the following illustrates an example of a bandwidth indexof 3 bits (b0b1b2) included in the HE-SIG A.

TABLE 22 * Bandwidth index (3 bits, b0b1b2) in HE-SIG A * 000: 20MHz *001: 40MHz * 010: 80MHz (preamble fully populated on all 4 channels andOFDMA uses 80MHz design) * 011: 160MHz (preamble fully populated on all8 channels and OFDMA uses 160MHz design) * 100: 80MHz channel bondingwith preamble on P40 * 101: 80MHz channel bonding with preamble on P20(no preamble on S20) * 110: 160MHz channel bonding with preamble on P40111: 160MHz channel bonding with preamble on P20 (no preamble on S20) }

100 and 101 indicate channel bonding information in primary 40 andprimary 20 (i.e., secondary 20 is not included), respectively, in a BWof 80 MHz and 110 and 111 indicate channel bonding information inprimary 40 and primary 20 (i.e., secondary 20 is not included),respectively, in a BW of 160 MHz.

In this case, detail null bandwidth information (or non-contiguouschannel information) included in HE-SIG B (in particular, HE-SIG Bcommon part) can be defined as examples described in the following.

A table 23 in the following illustrates an example of channel bondinginformation included in the HE-SIG B.

TABLE 23 * Channel bonding information (2 bits, b0b1) in HE-SIG B of80MHz (i.e., if a BW of the HE-SIG A corresponds to 100 and 101): b0indicates a first 20MHz channel of Secondary 40 and b1 indicates asecond 20MHz channel of Secondary 40. 0 indicates that the 20MHz channelis not used. * 01: indicates that the first 20MHz channel of Secondary40 is not used and the second 20MHz channel of Secondary 40 is usedonly. * 10: indicates that the first 20MHz channel of Secondary 40 isused and the second 20MHz channel of Secondary 40 is not used. * Channelbonding information (6 bits, b0b1b2b3b4b5) in HE-SIG B of 160MHz (i.e.,if a BW of the HE-SIG A corresponds to 110 and 111): b0 indicates afirst 20MHz channel of Secondary 40, b1 indicates a second 20MHz channelof Secondary 40, b2 indicates a first 20MHz channel of Secondary 80, b3indicates a second 20MHz channel of Secondary 80, b4 indicates a third20MHz channel of Secondary 80, and b5 indicates a fourth 20MHz channelof Secondary 80. 0 indicates that the 20MHz channel is not used and 1indicates that the 20MHz channel is used. * 011111: In Secondary 40 andSecondary 80, the first 20MHz channel of Secondary 40 is not used onlyand the remaining channels are used. * 101111: In Secondary 40 andSecondary 80, the second 20MHz channel of Secondary 40 is not used onlyand the remaining channels are used. The remaining bitmaps are similarlyapplied.

In the example above, resource allocation information (user fieldsrelated to RU allocation field (8 bits)) on channels corresponding tothe primary 20 (or primary 40) and channels corresponding to a bit setto 1 in the channel bonding information are additionally included in theHE-SIG B. For example, when a BW index of the HE SIG A corresponds to100 and the channel bonding information of the HE-SIG B corresponds to01, resource allocation (RU allocation) information on 242 unitscorresponding to a first channel and a fourth channel (e.g., secondchannels of primary 20 and primary 40) are included in the HE-SIG B ofthe CH1/CH4.

Using [1, 2, 1, 2] Structure of HE-SIG B

FIGS. 24 and 25 are diagrams for explaining a structure for transmittingHE-SIG B in a band equal to or wider than 80 MHz according to oneembodiment of the present invention.

Specifically, when a radio frame is transmitted on 80 MHz band, FIG. 24illustrates a case that resource regions A, B, C and D (in thefollowing, the resource regions can also be represented as HE-SIG B CH1, 2, 3, and 4) respectively corresponding to 20 MHz (242 tones) exist.If 4 channels corresponding to the resource regions exist, controlinformation of the HE-SIG B may have a form that the same controlinformation is repeatedly transmitted in CH 1 and CH 3 and a form thatthe same control information is repeatedly transmitted in CH 2 and CH 4.In particular, independent control information [1, 2] of two types mayhave a repeated structure in a form of [1, 2, 1, 2] in 4 channels.

In particular, as shown in FIG. 24, it is preferable that HE-SIG B of CH1 includes not only resource allocation information on a resource regionA but also resource allocation information on a resource region C. And,it is preferable that HE-SIG B of CH 2 includes not only resourceallocation information on a resource region B but also resourceallocation information on a resource region D.

Meanwhile, when a radio frame is transmitted on 160 MHz band, FIG. 25illustrates a case that channel allocation information on resourceregions A1, B1, C1, D1, A2, B2, C2, and D4 follows the type of repeatingthe [1, 2, 1, 2] structure. In particular, resource allocationinformation on the resource regions A1, C1, A2, and C2 are transmittedvia CH 1 and the resource allocation information can be repeated on CH3,CH5, and CH 7. In the same manner, resource allocation information onthe resource regions B1, D1, B2, and D2 are transmitted via CH 2 and theresource allocation information can be repeated on CH 4, CH 6, and CH 8.

If a BW field of the HE-SIG A indicates that a specific CH correspondsto a null channel under the abovementioned assumption, it may be able toindicate a location of the null channel via HE-SIG B which istransmitted via a channel which is not a null channel. For example, theBW field of the HE-SIG A can indicate that a BW corresponds to 80 MHzand a null channel of 20 MHz exists. In this case, if an actual nullchannel corresponds to CH 3, it is preferable not to transmit HE-SIG Bvia the CH 3. However, since CH 1 includes resource allocationinformation on the CH 3 due to the aforementioned [1, 2, 1, 2] structureand indicates that 242 tones corresponding to the CH 3 correspond to anempty resource region, it is able to indicate a specific location of anull channel.

In the abovementioned embodiment, resource allocation information (userfields related to RU allocation field (8 bits)) on channels of whichnull indication is set to 1 is additionally included in the HE-SIG B.For example, when a BW index of the HE-SIG A corresponds to 100 andchannel bonding information of the HE-SIG B corresponds to 01, HE-SIG Bof CH 1 includes an RU allocation field for 242 units corresponding to afirst channel, a third channel, and a fourth channel (e.g., a firstchannel and a second channel of primary 20 and secondary 40), an RUallocation field for a CH 3 indicates that 242 units corresponding tothe CH 3 correspond to null allocation, and a user field correspondingto 242 units of the CH 3 is not included. In the present example, amongreserved values of the RU allocation field included in the HE-SIG B, aspecific value indicates that 242 RUs corresponding to a certain channelare null and an STA is able to know that the 242 RUs are null via thespecific value.

A table described in the following illustrates a different example ofchannel bonding information transmitted via HE-SIG B.

TABLE 24 * Channel bonding information bitmap (1 bit, b0) in HE-SIG B of80MHz (i.e., when a BW of HE-SIG A corresponds to 100 and 101): InHE-SIG B of CH 1 (Primary 20) and CH 3 (first 20MHz of Secondary 40),corresponding information indicates whether or not CH 4 is used. InHE-SIG B of CH 2 (Secondary 20) and CH 4 (second 20MHz of Secondary 40),corresponding information indicates whether or not CH 3 is used. Channelbonding information bitmap (3 bits, b0b1b2) in HE-SIG B of 160MHz (i.e.,when a BW of HE-SIG A corresponds to 110 and 111): In HE-SIG B of CH 1(Primary 20), CH 3 (first 20MHz of Secondary 40), CH 5 (first 20MHz ofSecondary 80), and CH 7 (third 20MHz of Secondary 80), correspondinginformation indicates whether or not CH 4(b0), CH 6 (b1), and CH 8(b2)are used. In HE-SIG B of CH 2 (Secondary 20), CH 4 (second 20MHz ofSecondary 40), CH 6 (second 20MHz of Secondary 80), and CH 8 (fourth20MHz of Secondary 80), corresponding information indicates whether ornot CH 3 (b0), CH 5 (b1), and CH 7 (b2) are used.

In the abovementioned bitmap, resource allocation information (userfields related to RU allocation field (8 bits)) on channels (242 RUs)corresponding to a bit set to 1 is additionally included in the HE-SIGB. For example, when a BW index of the HE-SIG A corresponds to 100 andchannel bonding information of the HE-SIG B of the CH 1 corresponds to1, RU allocation fields for the CH 1, the CH 3, and the CH 4 aretransmitted in a manner of being included in a common part of the HE-SIGB of the CH 1.

When a BW index of the HE-SIG A corresponds to 101 and channel bondinginformation of the HE-SIG B of the CH 1 corresponds to 1, RU allocationfields for the CH 1, the CH 3, and the CH 4 are transmitted in a mannerof being included in a common part of the HE-SIG B of the CH 1. Ifchannel bonding information of the HE-SIG B of the CH 2 corresponds to0, RU allocation fields for the CH 2 and the CH 4 are transmitted in amanner of being included in a common part of the HE-SIG B of the CH 2.In this case, an RU allocation field for the CH 3 included in the HE-SIGB of the CH 1 indicates that RUs of 242 tones corresponding to the CH 3are null. In the present example, among reserved value of the RUallocation field, a specific value indicates that 242 RUs correspondingto a certain channel are null and an STA is able to know that the 242RUs are null via the specific value.

FIG. 26 is a block diagram illustrating an exemplary configuration of anAP (or a BS) and an STA (or a terminal) according to an embodiment ofthe present invention.

The AP 100 may include a processor 110, a memory 120, and a transceiver130. The STA 150 may include a processor 160, a memory 170, and atransceiver 180.

The transceivers 130 and 180 may transmit/receive radio signals and mayimplement a physical layer according to, for example, an IEEE 802system. The processors 110 and 160 may be connected to the transceivers130 and 180 to implement a physical layer and/or a MAC layer accordingto the IEEE 802 system. The processors 110 and 160 may be configured toperform operations in accordance with one or more combinations of thevarious embodiments of the invention described above. In addition,modules implementing the operations of the AP and the STA according tothe various embodiments of the present invention described above may bestored in the memories 120 and 170 and executed by the processors 110and 160. The memories 120 and 170 may be included in the processors 110and 160 or may be installed outside the processors 110 and 160 andconnected to the processors 110 and 160 by known means.

The above description of the AP 100 and the STA 150 may be applied to aBS and a terminal in other wireless communication systems (e.g.,LTE/LTE-A system), respectively.

The specific configuration of the AP and the STA may be implemented suchthat the above-described embodiments of the present invention areapplied independently or two or more of the embodiments are applied atthe same time. For the sake of clarity, redundant description will beomitted.

FIG. 27 illustrates an exemplary structure of a processor of an AP or anSTA according to an embodiment of the present invention.

The processor of the AP or STA may have a plurality of layers, and FIG.27 specifically illustrates a MAC sublayer 3810 and a physical layer3820 on a data link layer (DLL) among these layers. As shown in FIG. 27,the PHY 3820 may include a Physical Layer Convergence Procedure (PLCP)entity 3821 and a Physical Medium Dependent (PMD) entity 3822. The MACsublayer 3810 and the PHY 3820 both conceptually include a managemententity called an MLME (MAC Sublayer Management Entity) 3811. Theseentities 3811 and 3821 provide a layer management service interface inwhich the layer management function operates.

In order to provide correct MAC operation, an STA Management Entity(SME) 3830 exists in each STA. The SME 3830 is a layer-independententity that may be present in a separate management plane or may appearto be off to the side. Although the exact functions of the SME 3830 arenot specifically described in this document, the entity 3830 maygenerally appear to serve to collect layer-dependent states from variousLayer Management Entities (LMEs) and set layer-specific parameter valuessimilarly. The SME 3830 may typically perform these functions on behalfof the typical system management entity and implement a standardmanagement protocol.

The entities shown in FIG. 27 interact in various ways. FIG. 27 showssome examples of exchanging GET/SET primitives. The XX-GET.requestprimitive is used to request the value of a given MIB attribute(management information based attribute). The XX-GET.confirm primitivereturns an appropriate value of the MIB attribute information if theStatus is “Success”. Otherwise, it is used to return an error indicationin the Status field. The XX-SET.request primitive is used to requestthat the indicated MIB attribute be set to a given value. If the MIBattribute indicates a specific operation, it is requested that thecorresponding operation be performed. The XX-SET.confirm primitiveconfirms that the indicated MIB attribute is set to a requested value ifthe status is “Success”. Otherwise, it is used to return an errorcondition to the status field. If the MIB attribute indicates a specificoperation, this confirms that the operation has been performed.

As shown in FIG. 27, the MLME 3811 and SME 3830 may exchange variousMLME_GET/SET primitives through MLME_SAP 3850. In addition, variousPLCM_GET/SET primitives may be exchanged between the PLME 3821 and theSME 3830 via the PLME_SAP 3860 and may be exchanged between the MLME3811 and the PLME 3870 via the MLME-PLME_SAP 3870.

The embodiments of the present invention described above may beimplemented through various means. For example, the embodiments of thepresent invention may be implemented by hardware, firmware, software, ora combination thereof.

When implemented by hardware, a method according to embodiments of thepresent invention may be embodied as one or more application specificintegrated circuits (ASICs), one or more digital signal processors(DSPs), one or more digital signal processing devices (DSPDs), one ormore programmable logic devices (PLDs), one or more field programmablegate arrays (FPGAs), a processor, a controller, a microcontroller, amicroprocessor, etc.

When implemented by firmware or software, a method according toembodiments of the present invention may be embodied as a module, aprocedure, or a function that performs the functions or operationsdescribed above. Software code may be stored in a memory unit andexecuted by a processor. The memory unit is located at the interior orexterior of the processor and may transmit and receive data to and fromthe processor via various known means.

Preferred embodiments of the present invention have been described indetail above to allow those skilled in the art to implement and practicethe present invention. Although the preferred embodiments of the presentinvention have been described above, those skilled in the art willappreciate that various modifications and variations can be made in thepresent invention without departing from the spirit or scope of theinvention. Thus, the present invention is not intended to be limited tothe embodiments described herein, but is intended to have the widestscope consistent with the principles and novel features disclosedherein. While the present invention has been particularly shown anddescribed with reference to preferred embodiments thereof, it will beapparent to those skilled in the art that various modifications andvariations can be made in the present invention without departing fromthe spirit or scope of the invention. Such modifications are not to beconstrued individually from the spirit and scope of the presentdisclosure.

INDUSTRIAL APPLICABILITY

In this specification, both an article invention and a method inventionare explained, and the description of the two inventions may besupplemented as necessary.

What is claimed is:
 1. A method of transmitting a signal, which istransmitted by an STA (station) operating in a wireless LAN (WLAN)system using a multi user (MU) scheme, comprising the steps of:configuring a radio frame in which a signaling (SIG) field containingcontrol information and a data field for transmitting data arecontained, wherein the signaling field is configured to contain an SIG Afield containing bandwidth information indicating the whole bandwidthhaving a bandwidth wider than 20 MHz as much as 2^(n) times and an SIG Bfield containing user specific information; and transmitting the radioframe to one or more other STAs, wherein the bandwidth information ofthe SIG A field additionally indicates whether or not the wholebandwidth contains one or more 20 MHz bands (null channel) not used fortransmitting data.
 2. The method of claim 1, wherein the SIG B fieldadditionally contains information indicating a location of the nullchannel.
 3. The method of claim 2, wherein the SIG B field contains acommon part containing common control information and a user specificpart containing the user specific information and wherein theinformation indicating the location of the null channel is contained inthe common part.
 4. The method of claim 1, wherein the bandwidthinformation of the SIG A field has a form of a bit sequence of aprescribed length, wherein first region values of the bit sequenceindicate that the whole bandwidth having a bandwidth wider than 20 MHzas much as 2^(n) times is used for transmitting data without the nullchannel, and wherein second region values of the bit sequence indicatethat the whole bandwidth having the bandwidth wider than 20 MHz as muchas 2^(n) times contains the one or more null channels.
 5. The method ofclaim 4, wherein the first region values of the bit sequence contain 1,2, 3, and 4 and wherein 1, 2, 3, and 4 of the bit sequence indicate 20MHz, 40 MHz, 80 MHz, and 160 MHz, respectively.
 6. The method of claim1, wherein if the radio frame is transmitted on a bandwidth of 80 MHz,the SIG B field is transmitted via first to fourth channels each ofwhich corresponds to a band of 20 MHz and wherein SIG B field controlinformation, which is transmitted via the first channel and the secondchannel, makes a pair with the third channel and the fourth channel andis repeatedly transmitted via each of the pairs.
 7. The method of claim6, wherein if the bandwidth information of the SIG A field indicatesthat the null channel is contained in the whole bandwidth of 80 MHz, SIGB field control information, which is transmitted via a channel ratherthan the null channel among two channels making a pair, indicates alocation of the null channel.
 8. The method of claim 6, whereininformation indicating the location of the null channel among the SIG Bfield control information indicates that 242 tones corresponding to aspecific channel correspond to an empty resource region.
 9. The methodof claim 1, wherein if the radio frame is transmitted on a bandwidth of160 MHz, the SIG B field is transmitted via first to eighth channelseach of which corresponds to a band of 20 MHz, wherein SIG B fieldcontrol information, which is transmitted via the first channel, makes afirst pair with the third channel, the fifth channel, and the seventhchannel and is repeatedly transmitted via each of the channels, andwherein SIG B field control information, which is transmitted via thesecond channel, makes a second pair with the fourth channel, the sixthchannel, and the eighth channel and is repeatedly transmitted via eachof the channels.
 10. The method of claim 9, wherein if the bandwidthinformation of the SIG A field indicates that the null channel iscontained in the whole bandwidth of 160 MHz, SIG B field controlinformation, which is transmitted via a channel rather than the nullchannel of a pair containing the null channel among the first pair andthe second pair, indicates a location of the null channel.
 11. Themethod of claim 10, wherein information indicating the location of thenull channel among the SIG B field control information indicates that242 tones corresponding to a specific channel correspond to an emptyresource region.
 12. The method of claim 1, wherein if the wholebandwidth is equal to or wider than 80 MHz, the whole bandwidth containsa primary 20 MHz channel, a secondary 20 MHz channel, and a secondary 40MHz channel and wherein the primary 20 MHz channel is not configured asthe null channel.
 13. A method of receiving a signal, which is receivedby an STA (station) operating in a wireless LAN (WLAN) system using amulti user (MU) scheme, comprising the steps of: receiving a radio framein which a signaling (SIG) field containing control information and adata field for transmitting data are contained; and processing thereceived radio frame, wherein the signaling field contains an SIG Afield containing bandwidth information indicating the whole bandwidthhaving a bandwidth wider than 20 MHz as much as 2^(n) times and an SIG Bfield containing user specific information and wherein the bandwidthinformation of the SIG A field checks whether or not the whole bandwidthcontains one or more 20 MHz bands (null channel) not used fortransmitting data.
 14. An STA (station) capable of operating in awireless LAN (WLAN) system using a multi user (MU) scheme, comprising: aprocessor configured to configure a radio frame in which a signaling(SIG) field containing control information and a data field fortransmitting data are contained, wherein the signaling field isconfigured to contain an SIG A field containing bandwidth informationindicating the whole bandwidth having a bandwidth wider than 20 MHz asmuch as 2^(n) times and an SIG B field containing user specificinformation; and a transceiver configured to receive a radio frame fromthe processor and transmit the radio frame to one or more other STAs,wherein the processor is configured to make the bandwidth information ofthe SIG A field additionally indicate whether or not the whole bandwidthcontains one or more 20 MHz bands (null channel) not used fortransmitting data.
 15. An STA (station) capable of operating in awireless LAN (WLAN) system using a multi user (MU) scheme, comprising: atransceiver configured to receive a radio frame in which a signaling(SIG) field containing control information and a data field fortransmitting data are contained; and a processor configured to processthe radio frame received by the transceiver, wherein the signaling fieldcontains an SIG A field containing bandwidth information indicating thewhole bandwidth having a bandwidth wider than 20 MHz as much as 2^(n)times and an SIG B field containing user specific information andwherein the processor is configured to check whether or not the wholebandwidth contains one or more 20 MHz bands (null channel) not used fortransmitting data via the bandwidth information of the SIG A field.